Are you misreading “preparing” as literally any writing
“Prepare derivative works” means not just any writing, but literally anything creative. If you paint a picture of a character from a book, using specific details described in that book such as their appearance and name, you are creating a derivative work.
https://law.stackexchange.com/questions/78442/what-is-considered-a-derivative-work
Even that Wikipedia article goes into fair use.
Fair use carves out an exception for parody, criticism, discussion, and education. “Entertainment” or “because I like the series and these characters” are not one of those reasons. Fan fiction might qualify as parody though.
What effect on the market can there be for a fan remaster of a 20 year old game that isn’t for sale anymore? Hard to argue that doesn’t fall under fair use.
This is not how “the effect of the use upon the potential market for or the value of the copyrighted work” part of fair use works.
A company can create a work, sit on it for literally 100 years doing nothing with it and making not a single cent from it, then sue you for making a nonprofit fan work of it. Steamboat Willie is 95 years old and until just this year you could have been sued for drawing him. Note that, in the eyes of the law, Steamboat Willie is effectively a different character than Mickey Mouse.
Again, I cannot stress enough how it doesn’t matter at all whether you are personally profiting from something or whether you are affecting a market. The word “potential” in that quote above is doing a lot of work:
A father in the UK wanted to put spiderman on the grave stone of his 4 year old son who loved the character. Disney said “no”. Disney does not make tombstones. You are not eating into their profits by putting spiderman on a tombstone. And yet in the eyes of the law Disney has every right to stop you since they might decide to start up a tombstone business next week.
Nothing I have written here is legal advice.
EDIT: I am not a fan of any of this. I think you should be able to write nonprofit fanfiction without worrying that some corporation might sue you. I am on your side on this. But this is the reality we live in.
Someone doesn’t like windows because they put ads in their start menu: aww you’re sweet
Someone doesn’t like Ubuntu because they put ads in their start menu: hello, human resources?